Sigma Xi Presentation

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2. Introduction | Experiment | Analysis | ConclusionEngineering GoalTo investigate sources of natural anthocyanin or chlorophyll-baseddyes that produce the most efficientdye-sensitized solar cell.2 3. Introduction | Experiment | Analysis | ConclusionProblem and Objectiveo Sources of inexpensive, reliable, and sustainable energy have beengreatly sought after in recent years.o While the most efficient dye-sensitized solar cells employing noble-based dyes have reached efficiencies of approximately 12%, these areimpractical and costly due to limited resources.o Cells created from organic materials are more environmentally-friendlyand cost effective and have attained efficiencies of 7.9%. [3]o In this study, we explored the use of organic sources of chlorophyll andanthocyanin in devising an inexpensive method of producing solar cellsthat efficiently harness light energy.3 4. Introduction | Experiment | Analysis | ConclusionHypothesis A solar cell containing bothanthocyanin and chlorophyll dyeswould yield the most efficient solar celldue to the combined absorptioncapabilities of the molecules. 4 5. Introduction | Experiment | Analysis | ConclusionProcedure Summary1) Made dyes and generated absorbance spectra2) Constructed solar cells3) Tested efficiency 5 6. Introduction | Experiment | Analysis | ConclusionDye Selectiono In order to choose the dyes that may produce the mostefficient solar cells, we selected literature sources that includethe greatest amount of chlorophyll and anthocyanin.o The dyes that we obtained were:ChlorophyllAnthocyaninClover BlueberriesDamianaNandina BerriesCelery EggplantBroccoli BlackberriesLettuceBell Pepper-- Concord Grape Juice6 Fig. 1 7. Introduction | Experiment | Analysis | ConclusionDye Preparationo Anthocyanin Dyes: crush ~15 g of the material using a mortar and pestle in 40 mL ofa methanol/acetic acid/water solution that was in a 25:4:21 ratioby volume the mixture was passed through filter paper repeatedly until aclear liquid could be obtainedo Chlorophyll Dyes: place the samples (except Damiana) in boiling water for 30seconds to denature enzymes that would otherwise causechlorophyll degradation Crush each sample using a mortar and pestle in ethanol and againfiltered until the extract was clear For Damiana: crush the dry leaves and deposit this powder in a 4oz glass bottle half-filled with ethanol and agitated until theethanol had taken on a dark green tint; pass the dye through afilter.7 8. Introduction | Experiment | Analysis | ConclusionDye Testingo We tested each dye using UV-Vis absorption spectroscopyto choose the dyes (2 chlorophyll and 2 anthocyanin) with thegreatest range of absorption.o We analyzed the graphs based on the breadth of the curvesand not the magnitude. The breadth of the curve representsthe wavelengths attributed to each dye, while the magnitudeis only attributed to concentration. 8 9. Introduction | Experiment | Analysis | Conclusion9 Anthocyanin SpectrumWavelength (nm)Fig. 2 10. 10Introduction | Experiment | Analysis | Conclusion Chlorophyll Spectrum Wavelength (nm) Fig. 3 11. Introduction | Experiment | Analysis | ConclusionChoosing Dyeso After examining the chlorophyll and anthocyanin absorptionspectrums we deduced that the following dyes had the bestranges of absorption: Anthocyanin: blueberry and nandina berry dyes Chlorophyll: clover and damiana dyeso In order to obtain the most inclusive spectrum, we chose tomix the top chlorophyll and anthocyanin dyeso The hybrid dye showed to absorb in both the chlorophyll andanthocyanin wavelengths11 Fig. 4 12. 12Introduction | Experiment | Analysis | Conclusion Fig. 5 Top Dyes 13. Introduction | Experiment | Analysis | ConclusionSolar Cell Setup [6]1) Make TiO2 paste from dry powder and nitric acid.2) Coat the conductive side of a glass slide with TiO2 paste and anneal in kiln.3) Carbon coat the conductive side of the complementary slide over an openflame.4) Place the TiO2-coated slide in a petri dish of dye and leave for designatedamount of time.5) Sandwich the dyed and carbon coated slides and clip with binder clips.6) Add iodide electrolyte solution between the slides13 14. 14Introduction | Experiment | Analysis | Conclusion Solar Cell Construct Fig. 6 15. Introduction | Experiment | Analysis | ConclusionMeasurementso In order to minimize the influence of environmental factors onthe accuracy of our data, we tested our solar cells in acontrolled indoor environment.o We placed the solar cell 36 inches from a 660 Wattincandescent bulb.o We set up a circuit that we connected to our solar cell andmeasured the current and voltage using multimeters and apotentiometer [6]o Our circuit setup: 15Fig. 7 [6] 16. Introduction | Experiment | Analysis | Conclusion Data Processingo To compare the effectiveness of each solar cell, we calculated the averageefficiencies.o The power density of each cell was determined using the experimentally-determined values of current and voltage.o We calculated the power density of the lamp used and then the efficiencyof each solar cell.o We then compared the percentages of the different types of solar cells inorder to determine the most suitable dye for constructing solar cells. 16 17. Introduction | Experiment | Analysis | ConclusionExample Data ChartDamiana Solar Cell Results Voltage (mV) Current (uAmp) Current Density Power Density (mA/cm2)(mW/cm2) 54 550.014 0.00074 152480.012 0.0018 260400.010 0.0026 28335 0.0088 0.0025 29930 0.0075 0.0022 30826 0.0065 0.0020 31722 0.0055 0.0017 32319 0.0048 0.0015 32617 0.0043 0.0014 32714 0.0035 0.0011 33111 0.0028 0.00091 3339 0.002 0.0007 3347 0.002 0.0006 17 3346 0.002 0.0005Fig. 8 18. Introduction | Experiment | Analysis | Conclusion Initial Calculationso In order to consider the lamps light intensity in our calculations, wemeasured the lux of the lamp using a Vernier Light Probe. We used theequation below to convert Lux into Watts:o We then took the value obtained from above to measure the irradiance ofthe lamp:o From this, we calculated the percent efficiency of each cell through thefollowing equation: 18 19. Introduction | Experiment | Analysis | ConclusionFinal NumbersValues for Efficiency CalculationsLuxSurface AreaLuminosity Lamp Power Irradiance(m^2)Efficacy (lm/W)Intensity (W) 21,3060.4115.5560 0.034 Fig. 9 We used the formulas from the previous slide and the values from above to come upon the following percent efficiencies:Average Conversion Efficiencies of Solar Cells Average Efficiencies 1.8 1.41.5 1.2 11.2 0.8 0.6 .65 0.4 0.2 019 Blueberry Nandina CloverDamianaHybridFig. 10 20. Introduction | Experiment | Analysis | ConclusionDiscussiono Contrary to our hypothesis, we found that cells producedfrom Damiana dye had the greatest power density output.o Though the hybrid dye had a greater range of absorption, theefficiency measure of this cell was similar to that of pureanthocyanin. This is a likely result of the nature of TiO2 dye-adsorption on a molecular level.o The anthocyanin dye molecules absorbs to the porous TiO2within 15 minutes of staining, therefore occupying themajority of the slide, leaving little to no surface area for thecomparatively larger chlorophyll molecules, which takeapproximately 24 hours to fully bond.20 21. Introduction | Experiment | Analysis | Conclusion Conclusionso Based on relative efficiencies, the damiana chlorophyll dyeformed the most effective solar cell.o Solars cells synthesized from chlorophyll dyes most closelymimic the sun-harnessing power of natures plants.o As we could not account for all procedural inconsistencies,even solar cells created from the same dyes showed slightvariance in power output.21 22. Introduction | Experiment | Analysis | ConclusionFuture Worko Decrease rate of cell degradation by confining the Iodide electrolytein the cell place a layer of parafilm over the TiO2 and dye layers to seal offiodide solution and prevent evaporation.o Analyze amount of dye adherence to TiO2 use a thin-film of TiO2 and run it through a UV spectrum after dyeing the TiO2, place the slide in a solution of a knownconcentration and measure the change in that solutiono Different dyeing methods dyeing the hybrid cell with chlorophyll before anthocyanin dyeing in layerso Increase procedural uniformity larger sample size more trials 22 23. Introduction | Experiment | Analysis | Conclusion Bibliography [1] A., Sharifi, and Hassani B. "Extraction Methods and Stability of Color Extracted fromBarberry Pigments." International Journal of AgriScience 2(4) (2012): 320-27. Web.. [2] Berg, Jeremy M. "19.2.1 Photosynthetic Bacteria and the Photosynthetic Reaction Centersof Green Plants Have a Common Core." Light Absorption by Chlorophyll Induces ElectronTransfer. U.S. National Library of Medicine, 18 Feb. 0000. Web. 05 Mar. 2013. [3] Brian, OReagan, and Gratzel Michael. "A Low-cost, High-efficiency Solar Cell Based onDye-sensitized Colloidal TiO2 Films." Letters to Nature 353 (1991): 737-39. Web. 7 Jan. 2013.. [4] Cherepy, Nerine J.; Smestad, Greg P.; Grtzel, Michael; Zhang, Jin Z. (1997)."UltrafastElectron Injection: Implications for a Photoelectrochemical Cell Utilizing an Anthocyanin Dye-Sensitized TiO2 Nanocrystalline Electrode". The Journal of Physical Chemistry B 101 (45):934251. [5] Excited-State Electron Transfer in Anthocyanins and Related Flavylium Salts. PalmiraFerreira da Silva, Joo C. Lima, Frank H. Quina, and Antonio L. Maanita. The Journal ofPhysical Chemistry A 2004 108 (46), 10133-10140 23 24. Introduction | Experiment | Analysis | Conclusion Bibliography (cont.) [6] Fanis, Linda. "The Nanocrystalline Dye Sensitized Solar Cell." Nanocrystalline SolarCell Kit: Recreating Photosynthesis. 2nd ed. Madison, WA: University of Wisconsin